Plug and Check

Display

Monitor Test: Seven Patterns to Check Your Screen

Check a monitor's uniformity, gradients, colors, sharpness, geometry, backlight bleed and motion blur with full-screen test patterns. Free, in your browser.

Runs in your browser. Your results never leave this device. No upload, no sign-up.

In full screen, click or press → for the next pattern and ← to go back. In the motion test, ↑ and ↓ change the speed. Press Esc to stop. On a touch screen, tap or swipe.

  1. Uniformity

    Five full-screen grays, from dark gray to white.

    What to look for: brighter or darker patches, a glow in the corners, or a pink, green or yellow tint in one area. Dark gray shows clouding best.

  2. Gradients

    Ramps from black to gray, red, green and blue, across the screen and then down it.

    What to look for: smooth ramps. Visible steps or bands mean fewer shades are getting through to the screen.

  3. Colors

    Full-screen red, green, blue, cyan, magenta, yellow and white.

    What to look for: each color even from edge to edge, with no tinted area and no dots of another color.

  4. Sharpness and text

    Text from 6 to 24 pixels, then 1-pixel lines and checkerboards drawn for your screen's own pixels.

    What to look for: crisp letters and clean lines. Blur, shimmer or colored fringes point to scaling or the sharpness setting.

  5. Geometry

    A grid of squares with circles, reaching every edge of the screen.

    What to look for: round circles, square boxes, straight lines, and the thin outer frame visible on all four edges.

  6. Backlight bleed

    Pure black. Dim the room and set your usual brightness first.

    What to look for: light leaking in at the edges or corners. A glow that shifts as you move your head is IPS glow, not bleed.

  7. Motion blur

    A block moving across dark, gray and light backgrounds, at the speed you choose.

    What to look for: a trail behind the block (ghosting) or a bright or dark outline around it (overshoot).

    Speed

Your report

Run the test above. Your results will appear here as plain text you can paste into a support chat, a return request or a forum post.

How to test your monitor

  1. Set the monitor to its native resolution, reset its picture mode to the default, and turn off night light or Night Shift.
  2. Let the monitor warm up for a few minutes and wipe the screen. Dim the room for the backlight bleed test.
  3. Press Run all tests in order, or Full screen on one test. Move through the patterns with a click, a tap or →.
  4. Read the tip on each pattern. Press Esc to come back, and mark each test as fine or not.
  5. Copy the report when you're done, and check for faulty pixels with the dead pixel test.

What each pattern tells you

Uniformity

Backlights and OLED panels are rarely perfectly even. On dark gray you may see clouding, patches of brighter gray, or vignetting, where the edges are darker than the middle. On light gray and white, look for a tint that changes across the screen. Some unevenness is normal; patches you notice in everyday use are worth raising with the seller.

Gradients

Each ramp runs from black to full color in one sweep. Thin bands at regular steps mean the signal or the panel shows fewer shades than the ramp needs, which also makes skies and shadows in photos look stepped. Compare across and down: banding in only one direction can come from the panel's own processing.

Colors

Solid colors show tinted areas and uneven brightness that a busy picture hides. A sharp dot of the wrong color on any of them is a faulty subpixel; the dead pixel test explains what each kind means.

Sharpness and text

Small text and 1-pixel lines are the hardest things for a screen to show. If letters have colored edges or the line patterns blur or shimmer, the screen may not be at its native resolution, scaling may be stretching the picture, or the monitor's sharpness setting may be too high or too low. The lines are drawn for your screen's pixels, so they are exact only with browser zoom at 100%.

Geometry

Circles should be round and squares square. Ovals mean the picture is stretched, often because the resolution's shape doesn't match the screen. On a TV, a missing outer frame means overscan, which crops the edges; look for a picture size setting such as Just Scan or Screen Fit.

Backlight bleed

On an LCD, black is made by blocking a backlight, and some light always gets through. In a dark room, pure black shows where it leaks most, usually along the edges. OLED screens have no backlight, so on them black should stay completely dark.

Motion blur

Pixels need a few milliseconds to change from one shade to another. A slow change leaves a trail behind the moving block; an overdrive setting pushed too hard overshoots and adds a bright or dark outline. Compare the overdrive or response time levels in your monitor's menu and keep the one with the cleanest edges. A higher refresh rate also helps, so check yours with the refresh rate test.

Patterns look wrong? Try these fixes

Text and lines look blurry

The picture is probably being scaled: the system isn't at the screen's native resolution, or zoom is on.

Windows 11

  1. Open Settings → System → Display and set Display resolution to the option marked (Recommended).
  2. Leave Scale at the recommended value; scaling text is fine, but the resolution should be native.

macOS

  1. Open System Settings → Displays and choose Default for your display.

Browser

  1. Reset the page zoom with Ctrl+0 (Command+0 on a Mac), then open the pattern again.

Gradients show bands

Windows 11

  1. Turn off Night light in Settings → System → Display.
  2. If HDR is on, compare with it off: Settings → System → Display → HDR.

macOS

  1. In System Settings → Displays, turn off Night Shift and True Tone while testing, and set Color profile to your display's default.

Graphics and color software

  1. Turn off blue-light filter apps, and reset color settings in NVIDIA Control Panel, AMD Software or Intel's graphics app.
  2. Check the output color format there: RGB with full range and the highest color depth the monitor offers.

Black looks gray or colors look washed out

Over HDMI, the computer and the monitor can disagree on the RGB range, which lifts black to gray.

  1. In NVIDIA Control Panel, under Change resolution, set Output dynamic range to Full. In AMD Software, set Pixel Format to RGB full range.
  2. In the monitor's menu, set the HDMI range or black level to match, often called Full, High or Auto.
  3. Try DisplayPort if both the computer and the monitor have it.

The moving block leaves trails

  1. Find the overdrive setting in the monitor's menu. Makers name it differently: Overdrive, Response Time, Trace Free or AMA. Try each level.
  2. Make sure the monitor runs at its highest refresh rate: Settings → System → Display → Advanced display on Windows 11, System Settings → Displays on a Mac.

Full screen doesn't fill the screen

Some extensions and browser settings block full screen, and iPhones don't offer it to web pages at all. Try another browser on a computer; on an iPhone, the patterns fill the window instead, so turn the phone sideways.

Common questions

How do I test a new monitor?

Run the dead pixel test first, then the patterns on this page in order: uniformity, gradients, colors, sharpness, geometry, backlight bleed and motion blur. Use the monitor at its native resolution with its picture settings at their defaults. Do it while your retailer's return window is still open.

What is backlight bleed, and how much is normal?

Backlight bleed is light from an LCD's backlight leaking around the edges of the panel, seen as bright patches near the edges on a black screen. A little is common on LCD monitors and is easiest to see in a dark room at high brightness. If it is distracting in normal use with the lights on, ask your retailer about a replacement.

What is the difference between IPS glow and backlight bleed?

IPS glow is a silvery or warm sheen that changes when you move your head, and it comes from looking at an IPS panel at an angle. Backlight bleed stays in the same spots, usually at the edges, from any angle. Sitting straight in front of the screen at your normal distance makes the difference easy to see.

Why do I see bands in the gradient test?

Bands mean fewer shades are reaching the screen than the ramp needs. Common causes are a color filter such as night light, a picture mode that boosts contrast, a connection running at reduced color depth, or a panel that shows fewer shades. Turning off color filters and resetting the monitor's picture settings often helps.

What does the motion blur test show?

It moves a block across the screen so you can see how quickly the pixels change. A faint trail behind the block is ghosting; a bright or dark outline around it is overshoot, which usually means the overdrive or response time setting is too high. Try each level in the monitor's menu and keep the one with the cleanest edges.

Can this test calibrate my monitor's colors?

No. These patterns help you see problems by eye, but accurate color calibration needs a hardware colorimeter and its software. The test can still tell you whether colors look even and whether gradients are smooth.

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